Potentially fixed a navmesh issue

Small visual update

- Added more details to debris
- Added normal textures to many materials
- Added a point light on the second floor

Visual and sound improvement

Visual :

- Added fog textures outside the map
- Added more point lights and lamp meshes
- Lowered the specularity of the ground in some places

Gameplay :

- Fixed an issue where you could get outside the navmesh in some areas

Sound (Experimental) :

- Added fire, wind and ambient sound effects

better navmesh

better navmesh (I think)